Signaling system for railroads



Sept. 22, 1931'.

J. E. WILLING SIGNALING SYSTEM FOR RAILROADS Filed July z. 1929 Patented Sept. 22, 1931 UNITED STATES PATENT OFFICE JOSEPH E. WILLING, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL'COMPANY, OF ROCHESTER, NEW YORK SIGNALING SYSTEM FOR RAILROADS Application filed July 26,

This invention relates to railway signaling systems preferably of the light signal type, and more particularly to a power-off circuit arrangement for supplying the light signals with direct current derived from a battery 'in the event the alternating current voltage drops a small percentage below normal Modern light signal systems for railways usually include the provision of an alternating current transmission line extending along the railway track, with suitable rectifying means for charging local storage batteries located at the various signal locations. Although the light signals could be operated directly off of such trickle-charge battery, it is more expedient to supply the light signal with-alternating current when such is available and to transfer to the battery source in the event that alternating current supply is an interrupted entirely or the voltage of the alternating current source drops below a certain value. It is of course understood that a power-off relay supplied by alternating current from the transmission line could be used 26 to connect the light signal circuits to the alternating current source when such relay is energized and to connect said light signals to the battery when such relay is (lo-energized, this is however, very unsatisfactory in that it 30 is desirous to make such change-over not only upon a failure in the alternating current supply but also upon a slight decrease in the voltage transmitted.

In accordance with the present invention it is proposed to use. a series power-off relay connected in the charging circuit of the rectifier, this having a marginal advantage in that the change in charging current flow is very pronounced as compared with the change in the alternating current voltages applied, and for this reason, the series power-ofl current relay may be designed to transfer the load from the alternating current source to the battery upon a very small change in the alternating current voltage. A further advantage in the proposed construction is present in that it permits the use of a direct current relay which has-closer pick-up and'release margins of operation than has; an alternating current relay.

1929. Serial No. 381,239.

Other objects, purposes, and characteristic features of the present invention will in part be pointed out in the description hereinafter and in part be apparent from the accompanying drawings. In describing the invention in detail reference will be made to the accompanying single drawing showing one embodiment of the present invention.

7 Referring to the drawing the rails 1 of a railway system have been shown divided into blocks by insulating joints 2, of which the adjacent ends of the blocks I and J only have been shown. T he entrance to the block J is provided with a three-position light signal S including light signal units to indicate clear, caution, and danger and designated Gr, Y, and B, respectively. Although these signals, of which the signal S only'has been shown, may be controlled in any suitable way, for illustrative purposes they are controlled by a polar neutral track relay '1 adapted to supply energy to the green lamp G under clear traflic conditions, apply current to the caution lamp Y under caution traffic conditions, and apply current to the red lamp R when the track relay T is deenergized, namely, under danger traffic conditions.

As shown, the light signal S receives its energy from the secondary winding of the transformer 5 when the power-off relay P is energized, and receives its energizing current from the battery 6 when the power-off relay P is dc-energized.

The battery 6, constituting a reserve source of current supply is charged through the medium of the rectifier R connected to the secondary winding of the transformer 7. This rectifier R is preferably one of the cop peroxide-lead type, and preferably comprises four rectifying elements 11, 12, 13, and

14. During. the time that the right-hand terniinal of the secondary winding of transformer 7 is of positive polarity current will flow to the battery 6 through the'following circuit :beginning at the right-hand side of the secondary winding of transformer 7, wire 16, rectifying element 11, wire 17, relay P, wire 18, battery 6, wire 19, rectifying element 12, wire 20, back to the secondary winding of transformer? L Duringthe-next half of the cycle when the left-hand terminal of the secondary winding of transformer 7 is of positive polarity current will flow from the transformer 7 to the battery 6 through the following circuit :beginning at the lefthand terminal of the secondary winding, wire 20, rectifier element 14, wire 17 ,relay P, wire 18, battery 6, wire '19., rectifying element 13, wire 16, back to the secondary winding'of transformer 7.

sistance to'serve as the usual ballast resistance used in rectifying circuits,so that the energy supplied to this relay P may be charged off for this purpose. 7 V

This series power-off relay P not only serves as a series resistance to'keep the charging current within certain bounds, but also serves to transfer the light signal 'circuits from the secondary winding of transformer 5 to the battery 6 in case thecharging current falls below a certain value. By reason of the fact that the charging current is dependent upon the difference between the voltage of the battery and the voltage delivered by the rectifier B, it readily appears that only a very small drop in voltageon the transmission line 10 will cause the charging current to vary to a much greater extent, or in other words, a slight change in the voltage of the transmission line is manifested in the charging circuit by a big variation in chargring current. By reason of this characteristic of the circuit arrangement shown it is possible to transfer the light signal circuits from the V transformer 5'to the battery 6 automatically in response to a very small change in transmission line voltage. In this connection it is desired to point out that the relay'P is'preferably externally adjustable to pick up and drop on .difierent current values depending V on the particular adjustmentin effect. This in a closed circuit. The reason the power-oil relay P remains de-energized is, that it is contained in a closed circuit including the rectiiier R, which rectifier has its rectifying ele- 'ments so poled in the circuit as to restrict the fiow of current therein]. The circuit arrangement shown IS a veryefiicient one, 1n-

that the power-01f relay requires no additional energy by reason of the fact that if such" power oif relay were notused a series bal- ,last resistance of substantially equal resistance'would be required; It may be pointed out that the power-oil relay P is preferably designed to function on such pickup and dropaway currentsas not to drop to its de-energ zed position when the batteryt is fully The series power-0E relay P in practice contains sufficient' ohmic re-.

charged, although if desired this power-off relay P may be so designed. In this latter event the'light signal S would be transferred to the battery 6 in the event the battery 6 is .ment of the present invention, and having illustrated a rectifier of a particular type, it is desired to be understood that i'ectiflers of any suitable type may be employed, and that such rectifiers may be either of the single wave or double wave rectifying type, and may be either of the electrolytic, thermionic or copperoxide type; it is further desired to be understood that other additions and modifi-' cations may be made to adapt the invention to the particular problem encountered in practicing the same, all without departing from the spirit or scope of the present invention or the idea of means underlying the same, eX cept as demanded by the scope of tne following claims. V I

, What I claim as new is 1. In a light signal system for railroads, the combination with a light signal, and of means for supplying electrical energy for il luminating said li -ht signal comprising, an alternating'current source, a battery, a rectiher for charging said battery from said source elf-alternatingcurrent through a charging circuit, 'a power-offrelay included in said charging circuit, and contacts on said relay for connecting said li ht signal to said alternating current source-when said relay assumes its energized position and connecting said light signal to said battery when said relay assumes its (lo-energized position.

' 2. In a light signal system for'railroads, the

combination with a light signal, and of means forsupplying electrical energy for illuminating said light signals comprising, an alternating current source, a battery, a rectifier for-charging said battery on" of said source of alternating current through a charging circuit, a power-off relay included in series in said charging 'circuit,'and contacts on said relay for connectin said light sig 'nal to said alternating current source when said relay assumes its energized position and connecting said light signal to said battery when said relay assumes its de-energized position. g

8. In a light signal system for railroads, the combination with a light signal, and of means for supplying electrical energy for V illuminating said lightsignal comprising, an

alternatingcurrent source, a battery. a rectifierfo'r charging said battery off of said source of alternatingcurrent through a charging circuit, a power-off relay included in said charging circuit and contacts on said relay for'con iecting said light signal to said alter: .nating current source when-said relay assumes i its attracted position and connecting said light signal to said battery when said relay assumes its retracted position, said power-01f relay being designed to assume its detracted and contacts on said relay for connecting said light signal to said alternating current source when said relay assumes its energized position and connecting said light signal to said battery when said relay assumes its deenergized position, said power-off relay being designed to assume its de-energized position upon a decrease of the charging current to a value lower than the charging rate existing with normal alternating current voltage applied and the battery fully charged.

5. In a signal system for railroads, the combination with an electrically operated signal, and means for supplying electrical energy for operating said signal comprising, an alternating current source, a battery, a rectifier for charging said battery from said source of alternating current through a charging circuit, a power-off relay included in said charging circuit, and contacts on said relay for connecting said signal to said alternating current source when said relay assumes its energized position and connecting. said signal to said battery when said relay assumes its deenergized position.

6. In a signal system for railroads, the combination with a signal having an incan- -descent lamp associated therewith, and of means for supplying electrical energy for illuminating said lamp comprising, an alternating current source, a battery, a rectifier for charging said battery from said source of alternating current through a charging circuit, a power-off relay included in said charging circuit, and contacts on said relay for connecting said incandescent lamp to said alternating current source when said relay assumes its energized position and connecting said incandescent lamp to said battery when said relay assumes its de-energized position. 7

7. In combination, a battery for supplying current for railway signaling purposes, a source of alternating current, a rectifier for charging said battery from said alternating current source, and means for varying the rate of charging of said battery by said rectifier in accordance with the degree to which said battery has been charged.

8. In combination, a battery for supplying current for railway signaling purposes, a

source of alternating current, a rectifier for charging said battery from said alternating current source, and current responsive means included in series with said rectifier for varying the rate of charging of said battery by said rectifier in accordance with the degree to which said battery has been charged.

9. In combination, a battery for supplying current for railway signaling purposes, a source of alternating current, a rectifier for charging said battery from said alternating current source, a current consuming device, and means responsive to the degree of charge of said battery for causing said current consuming means to consume current from said battery it said battery has been charged to a predetermined extent.

10. In combination, a battery for supplying current for railway signaling purposes, a source of alternating current, a rectifier for charging said battery from said alternating current source, a current consuming device, and current responsive means included in series with said rectifier for Varying the rate of charging of said battery by connecting said current consuming device across said battery when said battery is charged to a predetermined extent.

11. In combination, a railway track, a signal for governing movement of trains over said track, a battery for supplying current to said signal, a source of alternating current for supplyin current to said signal, a rectifier for charging said battery from said alternating currentsource, and means effective upon failure of said alternating current source to disconnect said signal from said alternating current source and connect said signal to said battery and effective to connect said signal to said battery irrespective of the presence of said alternating current source when said battery has been charged to a predetermined extent.

In testimony whereof I aifix my signature.

JOSEPH E. WILLING. 

